The invention relates to new virus forms capable of causing lymphadenopathies which are capable of then developing into acquired immune deficiency syndrome (AIDS). The invention also applies to antigens which may be obtained from these viruses and other viruses having certain properties in common with them. It also concerns antibodies which may be induced against these various antigens. Lastly, the invention relates to using these antigens or antibodies in diagnosing certain AIDS forms and, with respect to some of these AIDS forms, to producing immunizing and vaccinating compositions against these retroviruses such as purified proteins, glycoproteins, recombinant proteins or synthetic peptides.
An article by F. Barre-Sinoussi et al. in Science, Vol 220: pp 868-871 [1983] describes the isolation of the first retrovirus which was known to be responsible for AIDS. European Patent Application 138,667 specifically describes diagnosis of AIDS and pre-AIDS by detection of the presence of antibodies against the virus through the use of certain virus extracts and particularly through the use of some of the viral proteins. This retrovirus is known generally as LAV. Since that time, other similar strains and variations of LAV have been isolated. Illustrative strains include HTLV-III and ARV. The expression Human Immunodeficiency Virus Type I, abbreviated HIV-I, has been coined to cover these designations and the corresponding viral strains. The set of viruses which are identical with or close to the initial isolate shall be called herein "LAV type 1" or "LAV-I".
The "LAV" set may be defined as a set of viruses either causing generalized and persistent polyadenopathies, or AIDS, and having in vitro a tropism for T4 cells wherein this retrovirus induces a cytopathogenic effect. These retroviruses have been found to be distinct from the other already known human retroviruses (HTLV-I and HTLV-II).
Even though the LAV virus does vary genetically rather substantially, the diverse strains isolated to date from African, Haitian, European and American patients have in common certain antigenic sites on their main proteins: p25 core protein; gp 110 envelope glycoprotein; and gp 41-43 transmembrane protein. As a result, the prototype strain LAV-I deposited at COLLECTION NATIONALE DES CULTURES DE MICRO-ORGANISMES (CNCM) Institute Pasteur, 28 rue du Docteur Roux, 75724 Paris Cedex 15, France, under No. I-232 may be used as an antigen strain to detect antibodies for all types of afflicted patients regardless of origin. For example, the HTLV-III virus isolated by R. C. Gallo et al. is presently being used to detect antibodies in blood donors and patients by means of ELISA, immunofluorescence, and "Western blot" (or immuno-print) techniques and RIPA (ratio immuno-precipitation assay).